Gales are forecast for Auckland, Waikato, Coromandel and Gisborne and a heavy rain warning is in place for Northland, Coromandel Peninsula and Bay of Plenty.
Dramatic radar images taken before midday show hundreds of lightning strikes moving east over Northland towards Auckland.
After a turbulent night of thunderstorms and high winds, a key highway on the eastern side of Coromandel Peninsula and rural roads in southeast Auckland remain closed because of flooding and slips.
State Highway 25 is closed at Whiritoa because of slips and between Opoutere, Whangamata, because of flooding.
This morningthe state highway loop around the peninsula was open to traffic after the waters receded and slips were cleared at Duck Creek. Other roads in the region have been affected by minor slips and in some places are down to one lane.
Motorists have been asked to take care driving around the peninsula.
Roads southeast of Auckland still remain closed by flooding.
More than 100 homes in Clevedon and Kawakawa Bay are without power after flooding and slips prevented crews from repairing lines.
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Flooding closed five primary schools and seven early childhood centres today, including Waiheke Island's primary, Opoutere, Whenuakite, Te Wharekura o Manaia and Coroglen schools. Other schools had opened across Coromandel but bus services were not running.
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It was a quieter night for emergency services after a month's worth of rain fell in parts of Northland, Auckland and Coromandel yesterday.
The torrential rain temporarily abated but firefighters were busy securing buildings in Te Aroha after wild winds damaged property.
The Thames-Coromandel District Council said overnight stormy weather had resulted in slips coming down in people's properties.
Council communications manager Laurna White said Civil Defence officials would today assess the latest damage and ensure people were safe.
Several people were evacuated yesterday afternoon, including 27 Otumoetai College pupils and two teachers at a surf camp at Whangamata.
They had spent the night at a motorcamp.
White said there were no more evacuations overnight.
Today officials were checking the extent of the damage before the next deluge.
"We are assessing the district roads at the moment so there are still road closures in place and in some places there are going to be slips that we will be clearing up over the next couple of hours," said White.
Vector said about 110 households in Clevedon, Kawakawa Bay and Whitford have not had power restored as crews could not reach the damaged lines because of flooding and slips.
A helicopter on Wednesday surveyed the damage and, depending on road closures and weather conditions, Vector hopes to reconnect residents this afternoon.
Hunua roads still closed by flooding include Tourist Rd and sections of Twilight, McNicol and East Coast roads. Others were down to one lane, including Clevedon-Kawakawa Rd, Kawakawa-Orere Rd, Orere Point Rd, Maraetai Coast Rd and North Rd.
On Wednesday the Fire Service responded to almost 200 weather-related call-outs across New Zealand in 24 hours.
Fire Service northern shift manager Jaron Phillips said wind and lightning caused the most damage overnight. A tree crashed on a house in Thames and another exploded into fire near Whangarei.
Fire crews had to secure windows and attach plywood to a building at the Te Aroha Golf Club after a side was blown in by high winds. Elsewhere in the Waikato township roofs were lifted and fences were flattened by the winds.
Efforts today are focused on mopping up before the region is hit again by a fresh bout of bad weather.
More rain is expected across Coromandel and Northland today. Both regions are under a heavy rain warning.
The MetService is forecasting heavy rain from midday today to Friday night, with another 150mm-180mm possible.
Niwa says the bulk of the Auckland rain should hit the Wellsford area.
Rival forecaster Weatherwatch.co.nz says it will generally be drier today in the North Island and most of the rain will fall at sea.
However, rain clouds would drift back to land later in the day bringing more heavy downpours across northern regions on Friday.
